The current chair chassis only can achieve the basic function of adjusting the height of chair to be adapted to the users. When it is related to the condition that the back needs to be tilted or the seat needs to be moved forward and backward, the controlling handle needs to be applied. For instance, when a handle is used to adjust the tilting angle of the seat, another handle is also needed to lock or unlock the tilting angle of the back. When we need to adjust the position of the seat, a handle will be needed. There is also another handle for the lifting of the seat. The number of the handles is quite a few, and this will have art influence on the aesthetic of the whole chair.
Height of the current chair can only be adjusted by pulling up the handle, but it can't be adjusted by rotating the handle in a full range.